a conductance study of the interaction between cs+, rb+, nh4+, k+, t1+ and ag+ ions and18-crown-6 (18c6), benzo-18-crown-6 (b18c6), dicyclohexyl-18-crown-6 (dc18c6),dicyclohexyl-24-crown-8 (dc24c8), dibenzo-24-crown-8 (db24c8) in different binarymixtures of acetonitrile (an) with dimethylsulfoxide (dmso) and dimethylformamide (dmf)at 25 °c has been carried out. formation constants of the result...

Carbonic anhydrase contains one firmly bound zinc ion per enzyme molecule (1). The metal ion, which can be dissociated in the presence of a chelating agent, is essential for catalytic activity, and it has been suggested that it is a part of the active site (2). Some other divalent metal ions also activate the metal-free enzyme. For example, Co2+ gives 45oj, of the activity of the native enzyme ...

the trace element contents on the surface originated from mineralization would depend to the thickness of the calcrete layer above the ore deposit on the surface. a very thick layer of calcrete may not allow for much dispersion of the elements of interest in the surface. these elements may be concentrated in non-magnetic and magnetic part of calcrete. based on the current research, mineralogica...

The structures of human glyoxalase I in complexes with S-(N-hydroxy-N-p-iodophenylcarbamoyl)glutathione (HIPC-GSH) and S-p-nitrobenzyloxycarbonylglutathione (NBC-GSH) have been determined at 2.0 and 1.72 A resolution, respectively. HIPC-GSH is a transition state analogue mimicking the enediolate intermediate that forms along the reaction pathway of glyoxalase I. In the structure, the hydroxycar...

Class B beta-lactamases or metallo-beta-lactamases (MBLs) require zinc ions to catalyse the hydrolysis of beta-lactam antibiotics such as penicillins, cephalosporins, carbapenems, and cephamycins. There are no clinically useful inhibitors against MBLs which are responsible for the resistance of some bacteria to antibiotics. There are two metal-ion binding sites that have different zinc ligands ...

The inhibition by bacitracin of the enzymatic dephosphorylation of C(55)-isoprenyl pyrophosphate is abolished by the addition of chelating agents. If, however, the chelating agent is added after a preincubation of bacitracin with a divalent cation and the lipid substrate, then its addition has little effect, indicating that bacitracin, metal ion, and C(55)-isoprenyl pyrophosphate form a complex...

background: combination of glycation and oxidation is associated with diabetes mellitus. the aim of this study was to clarify the effect of glycated proteins in presence of transition metal ions on production of reactive oxygen species (ros) in rat hepatocyte suspension.  methods: glycated albumin was prepared by incubation of bovine serum albumin with 100 mm glucose in 0.3 m phosphate buffer a...

in present study, molecular dynamics simulation of cadmium (ii), lead (ii) and copper (ii) removal from aqueous electrolyte solutions using the ion-exchange process with the zeolite particles was done. the results showed that, most of the particles had the highest affinity of ion exchanging with lead (ii) and the lowest affinity with copper (ii). the calculated mean ion-exchange ratios showed t...

the reaction of an equivalent of 2- mercaptoethyl ammonium chloride with an equivalent of 2,6-diformyl -4- methyl phenol produced monoamine which was reacted with half equivalent of 1,2-diamine ethane to produce ethylene-bis-6-(2-mercapto-ethyl-imine)-methyl -4- methyl phenol [h4l]. the ligand was reacted with metal ions[cr(iii), mn(ii), fe(ii), co(ii), ni(ii), cu(ii), zn(ii), cd(ii), and hg(ii...